


your head caught flame

by readbetweenthelions



Category: Shadowhunters (TV)
Genre: Anal Sex, Fuck Or Die, M/M
Language: English
Status: Completed
Published: 2017-06-30
Updated: 2017-06-30
Packaged: 2018-11-21 08:47:51
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 2,487
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/11353983
Author URL: https://archiveofourown.org/users/readbetweenthelions/pseuds/readbetweenthelions
Summary: “So the cure is having sex.”“With the person you desire the most. Plenty of people die from this, you know. Not everyone can have sex with Angelina Jolie or their seventh-grade English teacher, and the longer you go without it, the greater the physiological strain… until your heart stops. Jace. Who’s your person?”





	your head caught flame

**Author's Note:**

> thanks to anon on [tumblr](http://fakeandinspace.tumblr.com) for the prompt. i hope this is the fuck or die you've all been secretly waiting for.

“Magnus,” Jace gasps, stumbling through the doorway of Magnus’ loft.

“You look like hell,” Magnus says, studying Jace’s heavy sweat and heavier breathing.

“You’ve got to help me,” Jace says. “Demon – greater demon – some kind of spell.”

Magnus straightens and motions for Jace to come in. He puts Jace on a couch – his least favorite couch, Jace knows, and he's probably put Jace here so Jace's sweat doesn't soak into one of the good couches.

“What are your symptoms?” Magnus asks, turning Jace’s head this way and that by his chin.

“Everything hurts,” Jace says. “The demon, cursed me – didn’t feel anything at first, then I started getting… uh, horny. Uncomfortably. Figured I could take care of it myself but that made it worse and it feels like I’m on _fire_ , Magnus, you’ve got to do something.”

There’s a flash of recognition in Magnus’ eyes, then a frown twists his mouth.

“I’ll be honest with you, Jace – the prognosis isn’t great,” Magnus says. “I can’t lift this curse. The only way to lift it is to… well, it’s to have sex with the person you desire the most.”

Jace hisses a breath out through his teeth. “So the cure is having sex.”

“With the person you desire the most,” Magnus corrects. “Plenty of people die from this, you know. Not everyone can have sex with Angelina Jolie or their seventh-grade English teacher, and the longer you go without it, the greater the physiological strain… until your heart stops.”

The person he desires the most? Jace feels a sinking cold in his stomach as a counterpoint to the fiery pain in his veins. He grits his teeth, hard enough to produce an audible grinding sound.

“Jace. Who’s your person?”

Jace clenches so hard he thinks his jaw might crack. His nails are digging deep into his palms, on the verge of drawing blood. He feels hot, so extremely hot, like he needs to jump in a lake in winter and even that might not be enough. He knows who he needs, but…

“Jace?”

“Simon,” Jace chokes out, his body trembling with the fever and the mortification. “It’s Simon. That’s who I need.”

“Well,” Magnus says, “at least it’s not Angelina Jolie.”

Jace whimpers, feeling dizzy. Magnus turns his back on Jace and waves his hands, a portal popping into existence on the other side of the living room.

“Let’s get you to Simon,” Magnus says. He reaches out his arms and hauls Jace off the couch. Once he’s up, Jace staggers across the room until he’s standing in front of the portal, Magnus supporting him with a hand at one elbow.

“Do you want me to come with you, to explain the situation to Simon?” Magnus asks.

“No,” Jace says hastily. “No, by the Angel, you know too much already, I don’t need you to seduce him for me.”

Jace feels Magnus shrug, and Jace takes a step forward – a feat, considering the world feels like it’s spinning and he isn’t certain he’ll be putting that foot back down on solid ground. He thinks of Simon, and the boathouse where he’s likely hidden away, and steps through the portal.

Portal travel is disorienting at the best of times, and when Jace steps out into Simon’s boathouse, it’s all Jace can do to not throw up on the spot. He stands and does his best to look normal, though he knows that’s a pipe dream. His shirt is soaked through with sweat and so is his hair, and he must look white as a sheet.

“Jace?” Simon says, poking his head up over the gunwales of the canoe he’s been lying down in. Quicker than Jace’s eyes can track, Simon is down and standing in front of Jace.

“Simon,” Jace says, “I need you.”

“What for? A mission?”

“No, it’s – ” Jace starts. “It’s not a mission. Look, this is going to sound stupid and crazy but just – listen, please, I… there was a demon, it cursed me, and I need – you and I need to have sex. Now, as soon as possible.”

Simon’s eyes go wide. “What?” he says. “What – what do I have to do with this? The demon cursed _you_ , didn’t he?”

Jace gives Simon a flat look. “Look at me, Simon. I’m dying. Magnus says that the curse is that I have to fuck the person I desire most, or this fever is going to kill me.”

“The person you desire most?” Simon frowns. “And that’s… me.”

“Yes, Simon, it’s _you_ ,” Jace gasps. He casts his eyes around the room, desperate for something to sit on, but finds nothing in reach. He leans against a beam instead. “I wouldn’t have – said anything, ever, probably, because you probably aren’t interested in being with a guy, but I think about you all the time and – look, I’m asking for a favor. You’re here, and you’re not Angelina Jolie, just _please._ I don’t want to die.”

“Angelina Jolie?”

Jace shakes his head. Simon steps closer.

“You’re really sweaty,” Simon says. “Look, Jace, are you sure about this? I don’t know if we can do this – I mean, I don’t think you’re really in any condition to give consent.”

“Simon!” Jace shouts, desperate. “I wouldn’t be here, with you, if I didn’t want this even when I’m clear-headed. This isn’t how I would have wanted this to happen, but… I’d have – if you’d wanted me, we could have – taken things slower. But please, Simon, I’m going to _die._ ”

“Okay,” Simon says, taking Jace by the shoulders. “Okay, we can do this. I want to talk about it later, but – ”

Jace reaches out and takes a fistful of Simon’s shirt. “Simon, please kiss me.”

Simon nods and steps in closer, slipping his hand into the curve of Jace’s neck and bringing Jace’s mouth to his. Jace sighs. The kiss feels like a cold rag on his forehead, soothing the burning in his nerves slightly. Jace parts his lips and slides his tongue against Simon’s, chasing that relief.

They kiss for a few moments, but it’s not enough to break Jace’s fever. Slipping his hands under Simon’s shirt provides a tiny bit of a reprieve, but not enough. Jace is hard in his jeans, has been since he saw Simon, really, and he needs more than what Simon is giving him. Jace reaches down and undoes his own fly, the decrease in pressure a release, but not a reduction in the fever.

“How do you want to do this?” Simon asks.

Jace presses kisses to Simon’s neck, unwilling to let their skin part for even a moment. “You can do me, whatever, I just _need_ you.”

“You – _you_ want _me_ to top.”

Jace gives him an irritated look. “What, like there’s something wrong with it?” he says. “Look, I can top, if you want to bend over.”

“No, no, topping is fine,” Simon says hastily. “Um… here, or do you want to lie down? In one of the boats.”

“Here,” Jace says. He turns around and rests a forearm against the wood beam he’s been leaning against, pressing his sweaty forehead to his wrist and spreading his legs.

Simon pulls Jace’s pants and boxers down first, loose as they are on his hips. Jace’s shirt follows, and his clothes are summarily tossed away. The cool air feels good on Jace’s flushed, sweaty skin, but the curse still burns like fire in his veins, a pulsing, piercing agony with every racing heartbeat.

Simon stands behind him, his hands on Jace’s hips, thumbs pressing into the dimples on Jace’s back just above his pelvis.

“What’s this one?” Simon says, tracing a rune on Jace’s lower back.

Jace knows it by the position, and the cross that Simon traces that makes up the main body of the rune. “Calm anger,” Jace says, as patient as he can – though the patience doesn’t last. “Put your fingers in me, Simon, c’mon, _hurry_ – ”

“Let me get lube!” Simon says, and Jace is loath to let him leave, but Simon is quick enough that he is back from retrieving the bottle in seconds. Jace tries to breathe evenly and listens to Simon uncap the bottle of lube.

Jace hears Simon exhale a nervous breath, but then Jace feels one finger push inside, sliding slowly and slick with lube. It makes some of the burning pain dissipate, and Jace leans his head back on his shoulders and sighs with relief.

“More, Simon,” Jace says. “Please, move your finger, I’m begging you.”

Simon does as he’s told, pushing in and pulling out slowly at first, then picking up the pace when he sees Jace can handle it. The sensation eases the pain of the curse some, but not enough.

“More,” Jace begs again. Simon works a second finger into him, curls them a little, and brushes against Jace’s prostate. Jace gives a bark of surprise and feels precum dribble from his cock. Jace grinds back against Simon’s hand, forcing his fingers deeper, chasing that sensation again.

Simon’s fingers feel incredible, especially after the addition of a third, and Jace thinks maybe he could get off like this, given enough time – but he knows, instinctually, that this won’t lift the curse. It still feels like someone is trying to rip all of his nerves out of him, and the pain is maddening.

“I’m ready, Simon, fuck me.”

When Simon pulls his fingers out and leaves him again, Jace feels the fire in his veins blaze again, so painful that his legs wobble underneath him. He needs a rune for pain like this, but none of them will work – Jace already tried them before going to Magnus for help. The time it takes for Simon to roll on the condom is excruciating, an eternity, but soon Simon is pressing the blunt head of his cock to Jace’s hole and Jace cants his hips, pushing back against it, urging Simon to put it in him already.

Simon’s cock is thick, bigger than a few of his fingers, but the stretch of his hole around it is a drop in the bucket of Jace’s agony. It doesn’t last long. Easily half of the pain melts away when Simon bottoms out inside him, and Jace gives a long groan of relief.

“How does that feel?” Simon asks, pulling Jace out of his reverie.

“Amazing,” Jace responds. “It feels amazing. Keep going, shit…”

Simon works up a slow rhythm, letting Jace feel the full length of Simon’s cock as it slides into and pulls out of him, the delicious sensation beginning to replace the stinging pain. Simon pulls Jace close with one hand curled around Jace’s hip, and the other hand splays on Jace’s ass, pulling the cheeks apart with one thumb.

“Have you ever taken it like this before?” Simon asks, his words punctuated by thrusts that are picking up in pace now.

Jace swallows. “No.”

“Been with a guy before?”

“No.” Jace takes a steadying breath. “I’ve – fingered myself before. A couple times. But no guys.”

“I’m your _first_.”

Jace can hear Simon’s grin in his voice, and Jace rolls his eyes, hoping Simon will sense that. “Shut up,” he says, in case Simon doesn’t.

“I’ve been with a couple. Just oral,” Simon says, “not anal.”

Jace groans, the mental image of Simon on his knees sucking dick far too much for Jace to bear. He buries his face in his elbow and tries to focus on the feeling of Simon inside of him, on Simon’s cock rubbing his prostate with every thrust.

Simon and the full thickness of him are good, but it’s still not enough. Jace feels the curse pull at him, stretching too thin, like he might tear everywhere all at once. It won’t be over until he finishes, Jace knows. Jace gropes behind him, looking for Simon’s hand. He finds it, slips his fingers between Simon’s palm and his own ass and grabs Simon’s hand. Jace feels him squeeze for a brief second before Jace tugs Simon’s hand forward and brings it to his cock.

“I thought you were just being romantic for a second there,” Simon says. His fingers circle Jace around the base, then give a long, slow stroke up towards the tip.

“Romance later,” Jace pants. “Fucking now.”

Jace can feel Simon shrug behind him. Jace is surprised at Simon’s coordination as he times his strokes with his thrusts into Jace, a delicious mixture of sensations that has Jace edging closer to his climax with every second. Jace feels the pain from the demon curse begin to ebb away, like a long headache after you finally take something for it. Simon is good at this, _incredibly_ good, better than Jace imagined; Simon Lewis, of all people, who even in Jace’s fantasies was nervous and bumbling and needed Jace to show him the ropes. Simon kisses the back of Jace’s neck while he fucks him, and Jace swears he even feels teeth once or twice – not vampire canines, but incisors, a light scrape meant to excite Jace.

“How – ” Jace gasps, “you’re so good, Simon, how did you get this good at… oh, fuck…”

“I’m not a virgin or anything, you know,” Simon says. 

Jace knows he won’t last much longer. “Simon,” he sighs, “I’m close.”

In response, Simon picks up his pace slightly, fucking Jace quicker and stroking him faster until Jace feels his core clench, his balls tighten, and finally, finally, his mind white out as he comes, spilling onto Simon’s floor. It’s all Jace can do to remain standing afterwards. He feels it, the tremendous alleviation of all the pain that’s been plaguing him for what feels like days, the demon curse satisfied at last.

“Oh,” Simon says, softly, and his rhythm begins to falter. He leans forward until his chest is flush with Jace’s back and gives a few last thrusts before stalling, his cock twitching inside Jace as he finishes.

“Thank you,” Jace says, “thank you…”

Simon pulls out of him and backs away a step, leaving Jace clinging to the beam for support. Slowly, Jace lowers himself to sit on the floor of the boathouse, then flops backwards to lie flat on his back. He is exhausted, his muscles sore from the ordeal but no longer burning, the sweat finally drying on his skin. Simon strips off the condom and lies down next to him.

“So,” Simon says. “You have feelings for me?”

“Fuck, Simon,” Jace says. “I mean – I guess I do. I’m just… into you.”

“I could see us together,” Simon says. “I’m into you, too, Jace. And that – that was definitely worth doing a second time.”

Simon grins over at Jace and Jace shakes his head. He gives a moment’s pause and then reaches over to Simon across the expanse of floor between them and takes Simon’s hand. Simon gives him a surprised look.

“What?” Jace says, smirking. “You wanted romance.”


End file.
